How much is enough? Hematoma clearance thresholds and 30-day outcomes after sMIS for ICH across overall and baseline volume strata.

BACKGROUND: The prognostic relevance of hematoma clearance after stereotactic minimally invasive surgery (sMIS) for supratentorial intracerebral hemorrhage (ICH) remains incompletely defined. We evaluated the association between hematoma clearance rate (HCR) and 30-day functional outcome and explored clinically interpretable HCR thresholds. METHODS: We retrospectively analyzed 148 consecutive adults with spontaneous supratentorial ICH who underwent frame-based sMIS between January 2020 and December 2024. Preoperative and early postoperative non-contrast CT scans were segmented using 3D Slicer to derive preoperative hematoma volume, postoperative residual hematoma volume, intraoperative aspirated hematoma volume, and HCR. The primary outcome was 30-day unfavorable functional outcome, defined as modified Rankin Scale (mRS) 4-6. Multivariable logistic regression, generalized additive models, ROC analysis, threshold-based diagnostic performance analysis, interaction analysis, and sensitivity analysis were performed. The fully adjusted model included age, admission Glasgow Coma Scale category, preoperative hematoma volume, Barras morphology grade, international normalized ratio, hemoglobin, platelet count, onset-to-surgery time, and postoperative intracavitary thrombolysis. RESULTS: Of 148 patients, 73 achieved mRS 0-3 and 75 had mRS 4-6 at 30 days. Higher HCR was independently associated with lower odds of unfavorable outcome in the fully adjusted model (OR 0.91 per 1% increase, 95% CI 0.86-0.96; p < 0.001). This association remained robust after additional adjustment for postoperative intracranial rebleeding and intracranial infection (OR 0.89, 95% CI 0.84-0.95; p < 0.001). HCR showed good discrimination for unfavorable outcome, with an AUC of 0.837 and an approximate threshold near 60%. Compared with postoperative residual hematoma volume >15 mL, HCR < 60% showed higher sensitivity, negative predictive value, accuracy, and threshold-based AUC, whereas residual hematoma volume >15 mL showed higher specificity and positive predictive value. CONCLUSION: HCR after sMIS was independently associated with 30-day functional outcome and may serve as a postoperative prognostic benchmark. An HCR threshold near 60% may help risk stratification after sMIS and may complement absolute residual-volume thresholds such as 15 mL. Prospective multicenter validation is required before this threshold can be used as a prescriptive treatment target.